Helical thread gauging rolls



June 21, 1960 A. M. MAN

HELICAL THREAD GAUGING ROLLS Filed July 27, 1956 ALEXA/V051? M M4 N,Ema/roe.

lrrae -ey 2,941,304 HELICAL THREAD GAUGIN G ROLLS Alexander M. Man, 3456Carmona Ave., Los Angeles, Calif.

Filed July 27, 1956, Ser. No. 600,451 6 Claims. (Cl. 33199) Thisinvention relates to new and improved helical thread gauging rolls.

A number of different types of structures for measuring the pitchdiameter and the pitch of screw threads on various types of bolts andthe like are manufactured and sold in the United States at the presenttime. Conventional thread gauging rolls for these purposes are formed soas to have ridges and grooves located on the outside thereof. Structuresof this category can be characterized as being relatively expensive tomanufacture since they are normally formed out of high grade steel orthe like on a thread grinder to very close tolerances.

A basic object of the present invention is to provide thread gaugingrolls which are less expensive to manufacture than the above and otherrelated types of thread gauging rolls known at the present time. Anotherobject of the present invention is to provide thread gang ing rollswhich, in spite of their inexpensiveness, are accurate and are verysimple to manufacture. Further objects of this invention involve the useof thread gauging rolls as hereinafter described with attachments foruse with vernier calipers or the like, in U-shaped snap gauges, and inthread plug gauges of the so-called go and no go" category.

Other specific objects of the present invention as well as manyadvantages of it will be more fully apparent from the remainder of thisdescription, the appended claims, and the accompanying drawing in which:

Fig. 1 is a top elevational view showing the use of attachments andthread gauging rolls of the present invention with vernier calipers;

Fig. 2 is an isometric view, partially in section, showingan attachmentand a thread gauging roll as illustrated in Fig. 1;

Fig. 3 is an expanded isometric view showing the two parts of a threadgauging roll of this invention;

Fig. 4 is a partial cross sectional view illustrating the operation of athread gauging roll of this invention;

' Fig. 5 is a perspective view of a U-shaped snap gauge employing threadgauging rolls as defined herein; and

Fig. 6 is a top plan View of a thread plug gauge employing threadgauging rolls of this invention.

In all figures of the drawing like numerals are used to designate likeparts when convenient for purposes of illustration and explanation. Itis to be understood that this invention is not limited to structuressuch as are specifically illustrated inasmuch as the proportional sizesof the parts shown, such as for example, an attachment for use with avernier caliper, or the thread gauging rolls described may be changedconsiderably so as to adapt the invention for use With different sizedequipment and in measuring threads of various dimensions. All suchmodifications involving essentially a change in size, and not aifectingthe operating characteristics of the part involved are to be consideredas falling within the scope of this invention.

25,941,394 Patented June 21, 1960 As an aid to understanding the presentinvention, it may be stated in an essentially summary form that itinvolves thread gauging rolls each of which includes: a metal cylinder;a groove located on the outside of this cylinder so as to extend in ahelical path around it; and a wire coil positioned on the cylinder so asto be held by the groove in such a manner that this wire coil extendsfrom the cylinder itself so as to be capable of being used in measuring.The invention also encompasses the use of thread gauging rolls asdescribed in various operative mechanisms as will be hereinafterdiscussed. For a complete summary of the invention reference is made tothe appended claims setting forth in detail the features of thisinvention.

The invention is best explained by referring directly to theaccompanying drawing. In Fig. 1 there is shown a vernier caliper 10 ofconventional design and construction. Upon this caliper there are formedprojecting bar-like ends 12 used in measuring; upon these ends there arelocated attachments 14 of the present invention which are designed so asto convert the ca1iper'10 so that it may be used in measuring the pitchdiameter of threads. Each of the attachments 14 is built about anattaching member or block 16 having an elongated slot 18 locatedtherein. The ends 12 are adapted to fit within these slots 18 and to beheld firmly against the blocks 1-6 by means of yokes 20. As is best seenin Fig. 2 of the drawings the yokes 20 are pivotally attached by meansof screws 22'to the blocks 16, and are provided with adjusting screws 24used in securing the blocks 16 and the ends 12 to one another in theobvious manner. If desired, further screws 26 may be used so as tosecure the blocks 16 to the ends 12; also, if desired, various springmeans may be provided on the sides of the slots 18 so as to insure asnug fit against the ends 12, although this is not normally necessary.

When the attachments 14 are positioned as indicated, shafts 28 extendfrom these attachments in such a man ner as to rotatably support hollowmetal cylinders 30. These cylinders form the center or basic parts ofthread gauging rolls 32 of the present invention and fit closely againstthe shaft 28. Around the outside of each of the cylinders 30 there isformed a small groove 34 extending in a helical path and having auniform pitch. Preferably the grooves 34 are formed as with a lathe orgrinding apparatus in a conventional manner so as to have a number ofadjacent turns spaced from one another located around the cylinder 30 asshown in the drawing. A small wire coil 36 is adapted to be heldwithineach of the grooves 34 so as to extend radially therefrom and so thatadjacent turns of the coil 36 are spaced from one another as shown inthe drawing. These coils 36 are preferably formed in the manner of coilsprings out of wire having a uniform circular cross-sectionalconfiguration. Preferably the wire used for the coils 36 is veryaccurately formed as to diameter.

When the coils 36 are formed in the manner of coil springs they may beconveniently threaded upon the grooves 34 so as to be resiliently heldon the cylinders 30. If desired, they may be secured to these cylindersby various conventional means such as, for example, an adhesive, solderor the like, although this is not generally necessary. It should bespecifically noted that the coils 36 project from the cylinder 30 asillustrated in Fig. 4 so that the threads 38 on a bolt 40 or the likefit against the sides of the wire employed during use of the rolls 32.Thus, more than half of the wire used projects beyond the surface of thecylinder 30. Preferably the Wire is engaged by the thread at the pitchdiameter of the part being measured.

'The use of the thread gauging rolls 32 is considered to be obvious froma consideration of Figs. 1 and 4 of the drawings. When the attachments14 are attached as previously indicated to the caliper 10 this calipermaybe adjusted so that the threads "38 on a 'bolt'dl) may "be engaged'by the wire employed for the coils 36. By proper adjustment of thecaliper 10 a measurement is then obtained on the caliper whichcorresponds to the pitch diameter of the threads '33 on this/bolt 40.The reading obtained upon the caliper may then be corrected by an amountcorresponding to-the dimensions of the rolls 32 in order to obtain theactual pitch diameter of the threads 38. a

Since the pitch of the threads formed upon a bolt of any given externaldiameter may vary and since it is conventional to place threads uponbolts of many different diameters, it is preferred to supply a number ofdiiferent rolls of different thread pitches similar to the rolls 32along with the attachments 14. Thus, a complete set-of rolls 32can besupplied with two attachments '14 so that a singlecalipercan be used tomeasure any desired pitch diameter. These rolls 32 may be interchangedupon the shaft 28 :by merely removing-screws 42 from the ends of theseshafts. These screws 42 normally serveto hold the rolls .32 in position.If desired, conventional washers 45 can be supplied.

If desired, :the grooves 34can .be other than of a single pitch variety;in this case several interlocking coils 3.6 are :used, one coil in eachgroove. The method of construction employed in this case is the .samemethod .of construction as described in the foregoing. .A structure ofthis .category can be conveniently used .in measuring double pitchthreads .or the like. It is not to be assumed that the rolls 32 areuseful in-onlymeasuring pitch diameter. Because of the construction ofthese rollsthey can also :be employed to check the pitch of a thread.

It is also not to be assumed that the attachments 14 and the rolls 32are limited to use .in measuring external threads, inasmuch as they canbe'used :also in measuring internal threads.

If desired, thread gauging rolls as described can be mounted upon theends 44 of a U- haped frame 46 in a snap gauge (Fig. In this case theframe supports four shafts 48 arranged in pairs across the ends '44.Thread gauging rolls 32' are rotatably mounted upon these shafts byscrews 49 and all of theserollsare prefer: ably of the same diameter.The distance b between the outer pair of rolls 32 is slightly greaterthan the distance a between the inner-pair of rolls 32. Withrthisitypeof structure a bolt or the like may be passed through theinitial set of .rolls and will .be stopped from passing through thesecond set of rolls if the pitch diameter of the threads on it is withina permissible range of tolerances This type of structure is also usefulin checking threadpitch. If desired, various adjusting meanscan beprovided for setting the position of the rolls 32' on .this gauge, ordifferent sized rolls can be employed with it. In Fig. 6 of the drawingthere is shown .a thread plug gauge 50 of the present invention having.a handle 5210 the ends of which are rigidly secured shafts 54. On theseshafts thread gauging rolls or cylinders 32" are mounted by .means ofscrews 56 in such a manner that these rolls or cylinders are incapableof rotation. Preferably the two rolls or cylinders 32" ditler slightlyfrom o ie another in diameter corresponding to what are termed go" and'no go sizes so that this plug 50 maybe used .in-inspec tion productionwork such as isshown in Fig. 5 of the drawings.

Those skilled in the art to which thisinvention pertains will realizefrom the foregoing that the present invention is very simple, and thatthe thread gauging rolls described'herein are extremely easy tomanufacture to close tolerances. Further, these thread gauging rolls arevery accurate and eflicient for the purpose intended. Animpor'tantcommercial advantage of the invention lies in the fact that the coilsemployed can be easily replaced when worn; thus,'it is not necessary todiscard a complete worn gauging element. Since the present invention issusceptible to modification without departing from the essential conceptexplained herein, it is to be considered as being limited only by theappended claims.

I claim:

1. An attachment for use inrneasuring the pitch diameter of threads'uponra member which comprises: a block; means for securing said blockto a measuring instrument; a shaft extending from said block; a hollowmetal cylinder positioned around said'shaft; means defining a groove onthe outside of said cylinder, :said groove extending in a helical patharound said cylinder so as to have adjacent turns spaced from oneanother located around said cylinder; and a wire coil positioned on saidcylinder,

said wire in said coil being of larger diameter than the depth of saidgroove, said wire coil being located so as to be held by said groove andso as to extend from said cylinder, said coil having adjacentturnsspaced from one another. 7

2. A snap thread'gauge of the class described which comprises: agenerally U-shapedframe having ends; four shafts mountedparallel-tooneanother on the ends of said frame, two of said shafts=beingpositioned mom of said ends and two of said shafts beingpositioned on the other of said ends, so that said shafts are positionedin adjacent pairs, one of said shafts of each of said pairs beinglocated on each of said ends; a metal cylinder located'on each :of saidshafts; means defining a groove on the outside of each of saidcylinders, said grooves extending in helical paths and :having a uniformpitch, each of said grooves having adjacent turns spaced from oneanother located around said cylinder; and a wire coil positioned aroundeach ofsaid cylinders, said wire insaid coil being of larger diameterthan the depth of said groove, said coils being located so .as to beheld by said grooves and a so as :to extend :fromsaid cylinder, saidcoils each having adjacent turns spaced from one another.

3. An attachment for use inmeasuring the pitch diameterof threads :upona member which comprises: ablock; means for securing said block to ameasuring instrument; a shaft extending from said block; a hollowcylinder posi-. itioned around :said shaft; means defining a helicalgroove on the outside of said'cylinder, :said groove having a uni formpitch; and a :coiled wire spring positioned on said 1 cylinder, .saidwire in said spring being-of larger diameter than the depth of saidgroove and having a uniform cross-sectional configuration, said springbeing .locatedon said cylinder so as to extend into said groove so as tobe held'thereby and so as to extend from said cylinder.

4. A snap thread gauge of the class described which comprises: agenerally U-shaped frame having ends; four shafts mountedparallel to oneanother on the ends of said frame, two :of said shafts being positionedon one of said ends and two of .said shafts being positioned on theother of said ends so that said shafts are positioned in adjacent pairs,one of said shafts of each of said pairs being .locatedon each of saidends; a metal cylinder located on each of said shafts; means defining ahelical groove on the outside of each of said cylinders, said grooveshaving a uniform pitch; and a coiled wire spring positioned on each ofsaid cylinders, said wires in said springs being of larger diameter thanthe depths of said grooves and having a uniform cross-sectionalconfiguration, s'ai-d'springs being located on said cylinders so as toextend into said grooves so as to beheld thereby and so as to extendfrom said cylinders.

75. Athread plug gauge of the class described which comprises: anelongated handle; a cylinder attached to each end of said'handle, saidcylinders having slightly different diameters; means defining helicalgrooves on the outside of each of said cylinders, said grooves eachhaving a uniform pitch; and a coiled wire spring positioned on each ofsaid cylinders, said'wires in said springs being of larger diametersthan the depths of said grooves and each having a uniformcross-sectional configuration, said springs being located on saidcylinders so as to extend into said grooves so as to be held thereby andso as to extend from said cylinders.

6. A thread plug gauge of the class described which comprises: anelongated handle; a cylinder attached to each end of said handle; saidcylinders having slightly erent diameters; means defining groovesextending around said cylinders in a helical path so as to have adjacentturns spaced from one another located around said cylinders; and a wirecoil located on each of said cylinders so as to be held by said groovesand so as to extend from said cylinder, the diameter of the wire in eachof said coils being greater than the depth of the groove ReferencesCited in the file of this patent UNITED STATES PATENTS Lutz July 2, 1918Pettibone May -11, 1920 Summers Sept. 5, 1933 Johnston Jan. 1, 1935Taylor Sept. 12, 1944 Gabbey June 5, 1951 FOREIGN PATENTS Germany Aug.30, 1951 Germany June 18, 1953

